The present invention relates generally to an extension assembly, and more specifically, to an automated pivotal extension assembly for attachment to an open-top cargo box.
Extension apparatus for trucks or the like which increase the volume or height of the cargo area of such load carrying vehicles are known in the prior art. The body of prior art is comprised primarily of truck trailers utilizing vertically adjusting roof or sidewall assemblies. However, many of these apparatus lack sufficient strength, support and stability to ensure the safe containment and transit of loaded commodities. Furthermore, permanently attached and adjustable cargo box extensions of the kind found in the prior art generally require manual activation to complete the raising and lowering thereof. This requires much time and effort and often necessitates the operator to enter into the cargo box area.
An example of such an extension assembly can be found in U.S. Pat. No. 4,703,971 issued to Schmeichel et. al., on Nov. 3, 1987. The Schmeichel extension assembly includes a frame having an upper frame component and a lower frame component interconnected by a flexible fabric. The fabric becomes taut when the upper frame component is manually raised and reduces to a slack condition inside the cargo box area when the frame component is lowered.
The upper frame component is vertically supported by a plurality of horizontally spaced-apart jacks. Each jack must be separately activated in two stages by the operator during every lowering and raising process. Although aided by gas spring actuators attached to the ends of the upper and lower frames, the operator must enter inside the cargo box area to manually unpin and lift the upper frame component into its raised position. In addition, a heavy rolled-up tarpaulin cover must be simultaneously lifted with the upper frame component. This task requires great time, effort and agility from the operator. In addition, many open-top cargo box vehicles have sloped hopper floors which make raising and lowering movements especially difficult and hazardous.
Hence, there is a need for a simple, economical and effective automated pivotal extension assembly for attachment to an open-top cargo box; however, until now, no such assembly has been developed.